Crafts Reaction Conditions Research Articles

Effective Synthesis of 3-(2-Furyl)Phthalides Under the Friedel–Crafts Reaction Conditions

Effective Synthesis of 3-(2-Furyl)Phthalides Under the Friedel–Crafts Reaction Conditions

General asymmetric synthesis of 2,2,2-trifluoro-1-(1H-indol-3- and -2-yl)ethanamines

This work describes an asymmetric functionalization of the pyrrole ring of an indole structure with (2,2,2-trifluoro)ethylamine moiety allowing for general access to two novel classes of trifluoromethyl-containing indoles. We found that under the Friedel–Crafts reaction conditions (S)-N-tert-butylsulfinyl-3,3,3-trifluoroacetaldimine (1) easily reacts with indole derivatives affording the target 3-substituted products, while LDA-promoted reactions proceed exclusively at the 2-position. We demonstrate that both approaches feature wide substrate scope, high chemical yields and diastereoselectivities, which render these reactions readily applicable for straightforward preparation of biologically interesting compounds containing chiral CF3CH(NH2) and indole groups. The mechanistic rationales accounting for the observed mode of stereochemical preferences are proposed.

ChemInform Abstract: A Facile One Pot Conversion of Chalcones to Pyrimidine Thione Derivatives. Ring Opening Reactions of Oxiranes Derived from Chalcones.

Arylidene 2,5-dimethylacetophenones (1) reacted with thiourea and hydrogen peroxide to give pyrimidinethione (2) and oxirane derivatives (7), respectively. The behaviour of pyrimidinethione (2) towards hydrazine, acetylhydrazines, secondary amines under Michael reaction conditions, and phenylisocyanate has been investigated. The reaction of oxirane derivative (7) with aqueous sodium hydroxide, glacial acetic acid and p-xylene under Friedel Crafts reaction conditions is also described

Arylation of 3-heterylmethylene-5-arylfuran-2(3H)-thiones

The behaviour of 3-heterylmethylene-5-arylfuran-2(3 H)-thiones towards the Lewis acid AlCl3 under Friedel–Crafts reaction conditions compared with their oxygen analogues, the furan-2(3 H)-ones is studied. Although the later are known to undergo alkyl/oxygen ring cleavage to give resonance stabilised carbocations which can exhibit either intra- or intermolecular alkylations, furanthiones gave 1, 4-adducts with the furan ring remaining intact. This difference in behaviour is explained in terms of both electronic and steric effects.

Graphical Abstracts

Graphical Abstracts

Intramolecular Cyclization of 9,11‐Seco‐Estrane under Friedel–Crafts Reaction Conditions

Abstract An intramolecular cyclization of 17β‐acetoxy‐3‐methoxy‐9,11‐seco‐1,3,5(10)‐estratriene‐11‐oic acid under different Friedel–Crafts reaction conditions is described.

Quantum-chemical study of the electronic structure and reactivity of 2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylic acid methyl ester

We have used the MNDO approximation to carry out a quantum-chemical study showing that the selectivity of acylation of 2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylic acid methyl ester under Friedel—Crafts reaction conditions in the presence of AlCl3 depends more on the electron density distribution in the complexes than on the structure parameters.

Intramolecular Cyclization of 4‐Isocyanato‐3‐(2‐naphthyl)‐1‐phenylpyrazole under Friedel—Crafts Reaction Conditions.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Mechanism of Aromatic Hydrocarbon Acylation by Substituted Benzoic Acids: A Novel Reaction Pathway

Aromatic hydrocarbons are susceptible to direct acylation by benzoic acids with high yields bearing ortho or para alkyl groups as substituents under Friedel–Crafts reaction conditions. The α-H of the alkyl moiety seems to be responsible for the observed relatively high reaction rates of conversion. Carbanion-like species are proposed as reaction intermediates, which also operate as strong bases in the reaction rate-determining steps. Trapping experiments, deuterium isotopic effects, and kinetics data favor a concerted reaction pathway where proton transfer from the hydrocarbon molecule to a carbanionic intermediate takes place with a simultaneous electrophilic attack of the carbonylic carbon atom.

ChemInform Abstract: Synthesis of Novel 1-Methylindole Trimer and Tetramer under Friedel-Crafts Reaction Conditions and Determination of Their Structures by X-Ray Crystallography.

One-step synthesis of novel 1-methylindole trimer and tetramer under Friedel–Crafts reaction conditions is reported. The use of excess of the substrate and the catalyst and application of elevated temperature were necessary for success of the synthesis. The complete structures of the products were unambiguously elucidated by single-crystal X-ray analysis, and rationalization of their formation is attempted.

Synthesis of novel 1-methylindole trimer and tetramer under Friedel–Crafts reaction conditions and determination of their structures by X-ray crystallography

One-step synthesis of novel 1-methylindole trimer and tetramer under Friedel–Crafts reaction conditions is reported. The use of excess of the substrate and the catalyst and application of elevated temperature were necessary for success of the synthesis. The complete structures of the products were unambiguously elucidated by single-crystal X-ray analysis, and rationalization of their formation is attempted.

AlCl 3-Catalyzed regiospecific alkylation of aromatics with chlorobenzotrifluorides: A high yield preparation of 1,1-dichlorodiphenylmethanes

Chlorobenzotrifluorides ( 2 3 ), under typical Friedel - Crafts reaction conditions, react efficiently with aromatic compounds ( 1) to afford 1,1-dichlorodiphenylmethanes, ( 4) in excellent yield and purity.

ChemInform Abstract: Synthesis of 2‐Methylindole Analogues and Skatole Dimers under Friedel‐ Crafts Reaction Conditions.

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A FACILE ONE POT CONVERSION OF CHALCONES TO PYRIMIDINE THIONE DERIVATIVES. RING OPENING REACTIONS OF OXIRANES DERIVED FROM CHALCONES

Arylidene 2,5-dimethylacetophenones (1) reacted with thiourea and hydrogen peroxide to give pyrimidinethione (2) and oxirane derivatives (7), respectively. The behaviour of pyrimidinethione (2) towards hydrazine, acetylhydrazines, secondary amines under Michael reaction conditions, and phenylisocyanate has been investigated. The reaction of oxirane derivative (7) with aqueous sodium hydroxide, glacial acetic acid and p-xylene under Friedel Crafts reaction conditions is also described

Regiospecific C-9 substitution of ellipticine derivatives

6-Methylellipticine (6) undergoes acylation at the C(9)-position, under Friedel Crafts reaction conditions. The C(9)-formyl compound (8) rearranges to the corresponding hydroxy derivative (9) upon treatment with hydrogen peroxide, in methanol, in the presence of sulphuric acid. The two steps provide a convenient procedure for the specific C(9)-hydroxylation of the ellipticine template.

Synthesis of a novel ferrocene derivative having flame‐retardant and smoke‐suppressant properties

AbstractReaction of ferrocene with chlorendic anhydride (1,4,5,6,7,7‐hexachloro‐5‐norbornene‐2,3‐dicarboxylic acid anhydride) under Friedel–Crafts reaction conditions affords a new monosubstituted dervative of ferrocene which has significant flameretardant and smoke‐suppressant properties when incorporated into poly(vinyl chloride) (PVC). The monocarboxylic acid from the above reaction undergoes smooth methylation with diazomethane to give the corresponding methyl ester. 1H and 13C NMR spectra of these compounds have been compared with those obtained from similar compounds, namely β‐ferrocenoylpropanoic acid and its methyl ester. Distant asymmetric centres in the chlorendic anhydride substituent markedly affect the proton spectra of the ferrocene derivative.

Solvolytic extraction of coal through acylation and amidomethylation

Carboxylic acids, acid anhydrides and N-hydroxy methylamides were used to acylate Assam coal under Friedel—Crafts reaction conditions. This reaction resulted in the enhancement of the extractability of coal in benzene—methanol (7:3 vol./vol.) and quinoline after acylation with carboxylic acids and acid anhydrides. The effect of catalyst (AlCl 3) concentration on reaction was also investigated. l.r. spectra of reaction products indicated the introduction of acyl groups in the coal structure. Phthalimidomethylation could render about 50% coal extractable in quinoline.